Device for actuating a clutch or a gear box or the like

ABSTRACT

A device for actuating a system such as a clutch or a gearbox associated with an engine, particularly a motor vehicle engine, and comprising control element (26-31) and an actuation member (38). According to the invention, the device furthermore includes: 
     a first shaft (4) rotationally driven by the engine; 
     a second shaft (6) integral with the actuation member; 
     coupling member (10, 13, 15, 16, 33) for coupling the second shaft to the first shaft under the action of the control element; 
     a member (16, 32, 33; 48, 53) for uncoupling the second shaft from the first shaft after the second shaft has rotated through a predetermined angle; and 
     a return spring (35) for returning the second shaft to its initial position after it has been uncoupled from the first shaft.

BACKGROUND OF THE INVENTION

The present invention relates to a device for actuating a system such asa clutch or a gearbox associated with an engine, particularly a motorvehicle engine, and of the type comprising control means and anactuation member.

There currently exist various types of mechanical gearbox with orwithout automatic clutch, and automatic gearboxes.

Mechanical gearboxes are also known in which both the gear change andthe clutch are automatically controlled. Such automatic control involvescomplex and thus costly hydraulic or electrical systems which aredifficult to maintain and consequently reserved in practice, until now,for competition vehicles.

The present invention aims particularly to provide a device making itpossible to offer assistance to driving a motor vehicle which is simpleand relatively inexpensive, and more particularly making it possible toassist the gear-change and clutch-engagement maneuvers.

Document FR-A-877,118 discloses a device for actuating a system such asa clutch or a gearbox associated with an engine, particularly a motorvehicle engine, and comprising control means and an actuation member,and furthermore including:

a first shaft rotationally driven by the engine,

a second shaft integral with the actuation member,

coupling means for coupling the second shaft to the first shaft underthe action of the control means,

means for uncoupling the second shaft from the first shaft after thesecond shaft has rotated through a predetermined angle, and

return means for returning the second shaft to its initial positionafter it has been uncoupled from the first shaft.

More particularly, the coupling means are made up of a friction clutchincluding friction members, some of which are designed to be driven bythe first shaft, and others of which are capable of driving the secondshaft.

The friction members are coaxial with the first shaft, the firstfriction members being rotationally integral with the first shaft andthe second friction members being rotationally integral with a supportmember itself rotationally integral with a gear wheel meshing with atoothed sector rotationally integral with the second shaft.

This is therefore a mechanical device whose energy source consists ofthe engine itself. The power takeoff may, of course, be located in theregion of the output shaft of the engine or further downstream, forexample on the output shaft of the gearbox. The control member in thiscase is produced in the form of a pedal.

This device consequently operates like a mechanical amplifier of theforce exerted by the user.

It, however, exhibits the drawback that the user must make his actionlast until the end of the operating cycle. If the user fails to keep acontinued force on the pedal to the end of the operating cycle, thiscycle is interrupted and the operation of the device and of the memberswhich it controls is disturbed.

SUMMARY OF THE INVENTION

The present invention aims to overcome this drawback.

To this end, its subject is a device of the above-mentioned type,characterized in that it comprises means for keeping the coupling meanscoupled for as long as the second shaft has not made the said rotationthrough the predetermined angle.

Thus, the cycle finishes in all cases, even if the user interrupts hisaction.

More particularly, the holding means may comprise a cam and a camfollower, the rotation of the second shaft giving rise, by interactionof the cam and of the cam follower, firstly to the coupling of thesecond shaft to the first shaft and to their being held coupled, then,secondly, after the rotation through the predetermined angle, to theiruncoupling.

In a particular embodiment, the uncoupling means comprise two uncouplingmembers, one of the uncoupling members including a cam such as a slotand the other uncoupling member bearing a cam follower such as a fingercapable of moving in the slot, and one of the uncoupling members beingintegral with a casing of the device and the other uncoupling memberbeing designed to be displaced in a first direction via a movement ofthe second shaft, displacement of this member in the first directiongiving rise, through interaction of the cam follower and of the cam, toits displacement in a second direction which causes the second shaft tobe uncoupled from the first shaft.

The rotation of the second shaft consequently positively causes theuncoupling of the first and second shafts by interaction of theabove-mentioned finger and slot.

More particularly, the uncoupling member not integral with the casingmay be integral with the support member in terms of axial translation.

In a particular embodiment, inhibition means are provided for inhibitingthe return means for as long as the rotational speed of the first shaftis lower than a predetermined threshold.

In the case where the device is provided as assistance for clutchingengagement, such an arrangement makes it possible to use the device notonly during gear changes but also during starting.

The inhibition means may comprise pressing means for keeping thefriction members pressed together, and at least one flyweight forpushing the pressing means back when the rotational speed of the firstshaft exceeds the predetermined threshold.

More particularly, the holding means may comprise a cam designed tointeract with a cam follower finger integral with one of the frictionmembers, the cam being urged by elastic means in the direction ofkeeping the friction members in contact, and the flyweights acting onthe cam against the action of the elastic means.

Advantageously, the control means comprise elastic means designed tocontrol the device when they are freed by a user, and to be reset by thedevice during its operating cycle.

A control force is therefore available which is greater than that whichthe user is capable of providing.

BRIEF DESCRIPTION OF THE INVENTION

Particular embodiments of the invention will now be described by way ofnon-limiting example with reference to the appended drawings in which:

FIG. 1 is an axial section of a device according to the invention,

FIG. 2 is a view on a larger scale of the upper part of FIG. 1,

FIG. 3 is an axial section of the control member of the device of FIG.1,

FIG. 4 is a section on IV--IV of FIG. 3,

FIG. 5 is a view on a larger scale still of a detail of FIG. 2,

FIG. 6 is a developed section on VI--VI of FIG. 5,

FIG. 7a is a section on VII--VII of FIG. 2,

FIG. 7b is a view similar to FIG. 7a in another position of the membersrepresented,

FIGS. 8a and 8b illustrate the actuation of a gearbox and of a clutchwith the aid of a device according to the invention, and

FIG. 9 represents another embodiment of the control members.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The device first of all includes a casing 1, closed by two end flanges 2and 3.

A first shaft 4 is mounted in the casing 1 on rolling-contact bearings5, and a second shaft 6 is also mounted in the casing on rolling-contactbearings 7.

BRIEF DESCRIPTION OF THE DRAWINGS

A pulley 8 is mounted on the outside of the casing on the first shaft 4,to which it is rotationally linked by a key 9.

The first shaft 4 also carries, inside the casing 1, a disk-carryingmember 10, mounted to rotate on the shaft 4 by means of rolling-contactbearings 11.

The disk-carrier 10 includes, in a known fashion, a cylindrical partincluding a slot 12 in which projections of friction disks 13 areengaged in order to make the disks 13 and the disk-carrier 10rotationally integral.

Likewise, the shaft 4 includes a slot 14 in which projections offriction disks 15 which are interposed with the disks 13 are engaged, inorder to make the disks 15 and the shaft 4 rotationally integral. Theshaft 4, the disk-carrier 10 and the disks 13 and 15 are consequentlycoaxial.

A gear 16 with straight-cut teeth is mounted on the disk-carrier 10,rotationally integral with the latter by virtue of splines 17 andtranslationally integral by virtue of circlips 18.

An elastic washer 19 bearing, on the one hand, on the casing 1 and, onthe other hand, on the gear 16 by means of a rolling-contact bearing 20,pushes the gear 16, and consequently the disk-carrier 10, back towardthe left.

A pressure plate 23 makes it possible to clamp the friction disks,pressing them against a plate 24 forming the end of the cylindrical partof the disk-carrier 10, by means of a rolling-contact bearing 25.

If reference is now made to FIGS. 3 and 4, a control lever 26 can beseen connected to control means represented by a ball 27, and integralwith a control pin 28 returned to the neutral position with respect tothe flange 3 by a spring 29.

The part of the pin 28 opposite the lever 26 forms a flat 30 making itpossible to make the shaft 28 rotationally integral with an eccentric 31which, when the shaft 28 is rotationally driven, presses the pressureplate 23 so as to bring about a clamping of the disks 13 and 15.

Returning now to FIG. 1, it can be seen that the second shaft 6 isintegral with a toothed sector 33 with straight-cut teeth interactingwith the teeth of the gear 16.

The sector 33 forms a projection 34 on which one end of a hairpin spring35 bears, the other end of which bears on a rod 36 mounted in the flange2.

The end of the shaft 6 protruding from the flange 2 supports and isrotationally integral with an actuating lever 38 connected by means of aball 39 to the member, not represented, which is to be actuated.

The pressure plate 23 ensures the clamping of the disks 13, 15 by meansof an elastic washer 41. This clamping takes place against the plate 24of the disk-carrier 10 by means of an intermediate plate 42 of which afinger 42', projecting at its outer periphery, passes through the slot12 in order to interact with a slope 43 of a ring 44 sliding in thecasing 1 by virtue of splines 45. The slopes 43 are designed such that arotation of the disk-carrier 10 and of the intermediate plate 42 fromtheir rest position gives rise, on the ring 44, to a force toward theleft against the action of the elastic washer 19.

Flyweights 46 engaged in channels of the shaft 4 also tend to push theintermediate plate 42 back toward the left against the action of theelastic washer 19, when the shaft 4 is rotationally driven.

The gear 16 has a projection 47 supporting a cylindrical finger 48.

Another elastic washer 49 pushes the gear 16 back toward the right bymeans of a pressure ring 50 and of a rolling-contact bearing 51, againstthe action of the elastic washer 19.

A member 52 integral with the flange 2 includes a slot 53 forming aclosed track in which the free end of the finger 48 moves.

The finger 48 is represented in FIG. 6 in the rest position in which thegear 16 is in equilibrium between the actions of the elastic washers 19and 49.

Starting from this position, the track 53 includes a first part 54 whichslopes both with respect to the axial direction and with respect to thetangential direction as far as a position 55 of the finger 48, then asecond part 56 which slopes in the same direction as the part 54 withrespect to the tangential direction but in the opposite direction withrespect to the axial direction as far as a position 57 situated axiallyat the same level as the starting position, then a third part 58parallel to the part 54 and joining the position 57 to a position 59located at the same level as the starting position in the tangentialdirection, and finally a fourth axial part 60 connecting the position 59to the starting position. The track 53 therefore has substantially theshape of a right-angled trapezium with a right angle at position 55, andparts 54 and 56 extending with respect to the neutral positions axially48 and 57 toward the right of the member 52 and parts 58 and 60extending toward the left of these neutral positions axially.

The pulley 8 is rotationally driven, for example, by the engine withwhich is associated a gearbox which is to be controlled with the aid ofthe device. However, this pulley 8 may equally well be driven by theoutput shaft of this same gearbox, or by both these memberssimultaneously, by means of a differential gear train.

In operation, the first shaft 4 is consequently permanently rotationallydriven. For as long as the control lever 26 is not actuated, the disks15 are rotationally driven by the shaft 4 but the disks 13 remainstationary as, consequently, do the disk-carrier 10, the gear 16 and theshaft 6.

When the user acts on the control lever 26, he causes the pin 28 topivot, the eccentric 31 then exerts an axial force on the pressure plate23 which clamps up the disks 13, is consequently bringing about arotation of the disk-carrier 10 and of the gear 16 which itself drivesthe shaft 6 by means of the toothed sector 33.

At the beginning of this rotation of the gear 16, the finger 48 moves inthe part 54 of the track 53 from its starting position as far as theposition 55, which gives rise to a displacement of the gear 16 and ofthe disk-carrier 10 toward the right, and consequently automaticengagement of the clutch made up of the disks 13 and 15. The clutch isthus clamped between the disk-carrier 10 and the eccentric 31 under theaction of the elastic washer 41.

Then, still under the effect of the torque of the clutch, the finger 48moves in the part 56 of the track 53 thus returning the disk-carriertoward the left and freeing the clutch of any pressure. The hairpinspring 35 then returns the shaft 6 to its starting position, this shaftin turn returning the gear 16 so that the finger 48 runs along the part58 of the track 53 and arrives at position 59. The elastic washer 49 canthen act and returns the finger 48 to its starting position.

Of course, the actuating lever 38 has effected the desired action duringthe travel of the finger through the parts 54 and 56 of the track 53 andis then returned to its starting position. The angle through which theshaft 6 has turned corresponds to the angular difference between thestarting position and the position 57 of the finger 48, to within thedemultiplication factor.

This device is automatically controlled by the rotational speed of theshaft 4.

Indeed, when the finger 48 moves in the part 56 of the track 53 andarrives in the vicinity of the position 57, the finger 42 of theintermediate plate 41 mounts the slope 43 of the ring 44 thuscompressing the elastic washer 19 and producing, on the clutch, an axialforce which holds the finger 48 in position 57, the compression force ofthe clutch due to the washer 19 giving rise to a torque in this clutchwhich is greater than that of the spring 35.

Under the effect of an increase in the rotational speed of the shaft 4,the flyweights 46 provide a force which is opposite to that of theelastic washer 19 which force is sufficient to relieve the clutch of theaxial force due to this washer 19. Then the springs 35 and 49 return thefinger to the position 59 and to the starting position as describedpreviously.

Consequently, a simple action from the user is sufficient to trigger thedesired actuation, owing to the automatic clamping of the clutch. Thecycle then takes place automatically.

In addition, owing to the automatic speed control, this device is wellsuited to controlling a clutch.

FIGS. 8 illustrate one use of the device for controlling a clutch and agearbox.

The lever 38 here controls the clutch cable 63, and the ball 39controls, by means of the forked lever 62, the selection barrel 64 ofthe gearbox in the same manner as in motorcycles. The lever 62 ispressed by a hairpin spring 61 against a stop 69.

The lever 38 forms a cam 65 interacting with a cam follower formed byanother lever 66 to which the cable 63 for bringing about clutch releaseis connected.

During the clutch release travel of the lever 38, a clearance betweenthe lever 62 and the selection barrel 64 allows clutch release, afterwhich the barrel is driven by the fork 67 of the lever 62 while thecam-follower lever 66 progresses along a neutral part 68 of the lever38.

When the shaft 6 returns to its starting position, the fork 67 isdisengaged from the selection barrel 64 and the cam-follower lever 66runs back down the cam surface 65, reengaging the engine.

FIG. 9 represents a variant of the control means in which the controlacts on a lever 69a against the action of a spring 70. The lever 69forms a hook 71 interacting with an edge of the control lever 26 whichis here held bearing on the hook 71 via a spring 72, connected to thecasing 1.

When the user makes the lever 69a pivot, the control lever 26 escapesfrom the tip of the hook 71 and the lever 26 is rotationally driven bythe spring 72, in turn driving the control pin 28 and bringing about thedesired action.

When the pressure plate 23 returns the eccentric 31 to its startingposition, the lever 26 is itself returned against the action of thespring 72 and reengages in the hook 71 of the lever 69a by virtue of thespring 70.

The invention has been described with reference to the gearbox andclutch of a motor vehicle, but other applications, particularlystationary applications, may of course be envisaged.

Moreover, in the case where the forces to be exerted were verysignificant, it would be possible to place two devices according to theinvention in series, the output shaft 6 of the first device constitutingthe control shaft 28 of the second.

Moreover, there has here been described a friction clutch consisting ofa disk clutch, but a cone clutch or hydrodynamic clutch could just aswell be used.

Finally, it will be noted that the control of the device according tothe invention may easily be automated, with the vehicle then behavinglike a vehicle with an automatic gearbox.

I claim:
 1. Device for actuating a clutch or a gearbox associated withan engine, said device comprising control means (26-31) and an actuationmember (38), and furthermore including:a first shaft (4) adapted to berotationally driven by the engine: a second shaft (6) integral with theactuation member; coupling means (10, 13, 15, 16, 33) for coupling thesecond shaft to the first shaft under the action of the control means;means (48, 53) for uncoupling the second shaft from the first shaftafter the second shaft has rotated through a predetermined angle; andreturn means (35) for returning the second shaft to its initialposition, prior to the rotation thereof, after it has been uncoupledfrom the first shaft; the improvement comprising automatic means (48,53) for keeping the coupling means coupled for as long as the secondshaft has not made a rotation through the predetermined angle.
 2. Deviceaccording to claim 1, in which the means for keeping the coupling meanscoupled comprises a cam (53) and a cam follower (48), the rotation ofthe second shaft giving rise, by interaction of the cam and of the camfollower, firstly to the coupling of the second shaft to the first shaftand to their being held coupled, then secondly, after the rotationthrough a predetermined angle, to their uncoupling.
 3. Device accordingto claim 1 in which the uncoupling means comprise two uncoupling members(47, 52), one of the uncoupling members (52) including a cam (53) andthe other uncoupling member (47) bearing a cam follower (48) capable ofmoving around the cam, and one of the uncoupling members (52) beingintegral with a casing (1) of the device and the other uncoupling member(47) being designed to be displaced in a first direction via arotational movement of the second shaft, displacement of this member inthe first direction giving rise, through interaction of the cam followerand of the cam, to its displacement in a second direction which causesthe second shaft to be uncoupled from the first shaft.
 4. Deviceaccording to claim 2, in which the cam is a slot and the cam follower isa finger engaged in the slot.
 5. Device according to claim 2, in whichtwo friction members are coaxial with the first shaft, the firstfriction member being rotationally integral with the first shaft and thesecond friction member being rotationally integral with a support member(10) itself rotationally integral with a gear wheel (16) meshing with atoothed sector (33) rotationally integral with the second shaft, and inwhich the uncoupling member (47) not integral with the casing isintegral with the support member (10) in terms of axial translation. 6.Device according to claim 5, comprising inhibition means (19, 42-46) forinhibiting the return means for as long as rotational speed of the firstshaft is lower than a predetermined threshold.
 7. Device according toclaim 6, in which the coupling means comprise a friction clutchincluding at least two friction members (13, 15), one (15) of which isdesigned to be driven by the first shaft and the other (13) of which iscapable of driving the second shaft, and in which the inhibition meanscomprise pressing means (19) for keeping the friction members pressedtogether, and at least one flyweight (46) for pushing the pressing meansback when the rotational speed of the first shaft exceeds thepredetermined threshold.
 8. Device according to claim 7, in which theholding means comprise a cam (43) designed to interact with a camfollower finger (42) integral with one of the friction members, thedevice further comprising elastic means (19), with the cam being urgedby the elastic means (19) towards the friction members, and wherein theflyweights supply a force on the cam in a direction opposite to theforce supplied by the elastic means.
 9. Device according to claim 8,wherein the control means comprise elastic means (72) adapted toautomatically operate the device when the control means is freed by theuser, and wherein the control means is reset by the device during theoperating cycle thereof.
 10. Device according to claim 1, wherein theengine is a motor vehicle engine.